Thickness detector of paper

ABSTRACT

A paper-sheet-thickness detecting device includes a reference roller provided on a fixed rotation shaft; a detection roller provided to face and come into contact with the reference roller; a detection block in which the detection roller is provided at one end and the other end is rotatably fixed around a fulcrum shaft so that the detection block is turned and displaced according to a thickness of a paper sheet passing through between the reference and detection rollers; a holding block that holds the fulcrum shaft; a first pressing member fixed to the holding block to maintain contact between the detection and reference rollers by pressing the detection block, the first pressing member being displaced according to rotation and displacement of the detection block when the paper sheet passes through between the reference and detection rollers; and a displacement detector that detects a displacement amount of the first pressing member.

TECHNICAL FIELD

The present invention relates to a paper-sheet-thickness detectingdevice incorporated in a banknote recognition unit in a cash handlingmachine installed at a bank or the like to detect thickness ofbanknotes.

BACKGROUND ART

In an apparatus that handles banknotes, such as a banknote recognitionunit provided in a cash handling machine or the like and an automaticvending machine, it is important to recognize a banknote altered by atape, paper or the like, and the banknote recognition unit is providedfor the recognition.

The banknote altering techniques have been sophisticated particularly inrecent years. For example, banknotes, securities, stamps, and checksaltering by a tape, paper, or seal have been circulated.

As an example of a banknote judgment unit that authenticates banknotesor the like altered by a tape, paper or the like, there is aconventional technique described in Japanese Utility Model ApplicationLaid-open No. H6-49442, for example.

A paper-sheet-thickness detecting device in this conventional techniqueis explained with reference to FIG. 11. As shown in FIG. 11, a referenceroller 101 and a detection roller 102 are provided to face each other,and the detection roller 102 is attached to one end of a lever member104 swingable vertically around a fulcrum shaft 103 by a movable shaft105, and a douser 106 is attached to the other end of the lever member104. An optical sensor 107 such as a photo interrupter is arrangedfacing to the douser 106. The lever member 104 is biased upward by aspring 108 at a position away from the movable shaft 105, putting thefulcrum shaft 103 therebetween, and the detection roller 102 is pusheddown by this bias. However, the lever member 104 is locked by a lockingmember 109 so that a gap d between the detection roller 102 and thereference roller 101 becomes wider than a thickness t of a paper sheet Pand narrower than a thickness 2 t of two paper sheets.

Therefore, if only one paper sheet P is inserted, the movable shaft 105does not move vertically, and there is no change in a detection resultof the optical sensor 107. If two paper sheets are inserted together,the detection roller 102 is pushed upward to move the douser 106 via thelever member 104, and the detection result of the optical sensor 107changes. The thickness of the paper sheet is detected with thisconfiguration.

In the conventional technique, however, a setting operation of the gap dbetween the detection roller 102 and the reference roller 101 becomesquite difficult. Further, even if the gap d can be accurately set, thegap d may often go out of order during use.

Furthermore, in the conventional technique, the detection roller isalways brought into contact with the reference roller. However, if thedetection roller is always brought into contact with the referenceroller, a tremor (pitching) of the detection roller occurs duringpassage of a paper sheet, thereby causing a problem such that thethickness cannot be detected accurately.

Further, when the paper sheet passes through between the detectionroller and the reference roller, fine dust adhered to the surface of thepaper sheet adheres to the detection roller and the reference roller,and if the roller is coated with the dust, accurate detection cannot beperformed. Regarding this problem, a scraper for removing a foreignsubstance is disclosed in Japanese Laid-open Patent Publication No.H10-283520. However, if the scraper is secured to a part of anapparatus, even in the case of an elastic scraper, a movement of adetection roller when a banknote comes in between the rollers is blockeddue to an end of the scraper, and thus accurate thickness detectioncannot be performed.

Moreover, when thickness detection is performed for the entire surfaceof a paper sheet by arranging a plurality of detection blocks includingthe detection rollers in a direction orthogonal to a transport directionof the paper sheet so that the detection rollers come into contact withthe entire surface of the transported paper sheet, the paper sheet bumpsagainst all the detection rollers at a time. Therefore, the detectionblocks move abruptly due to a shock thereof, and a kick appears in anacquired detection output waveform. Furthermore, there is such a problemthat paper jam occurs due to a resistance when the paper sheet bumpsagainst the detection roller.

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

The present invention has been achieved to solve the various problemsmentioned above. Therefore, an object of the present invention is toprovide a paper-sheet-thickness detecting device that enables thicknessdetection as well as detection of a taped part, without requiring fineadjustment at the time of setting a detection roller, can reduce a kickin an output waveform when a paper sheet bumps against the detectionroller, and does not restrict a movement of the detection roller or areference roller at the time of removing a foreign substance adhered tothe detection roller or the reference roller.

Furthermore, conventionally, because a biasing unit for bringing thedetection roller into contact with the reference roller at all times anda detector that detects a displacement of the detection roller areconfigured by separate members, the configuration of the detectionroller is complicated. Therefore, another object of the presentinvention is to simplify the configuration of the detection roller byconfiguring the biasing unit and the detector by one member.

Means for Solving Problem

The present invention relates to a paper-sheet-thickness detectingdevice. The object of the invention is achieved by apaper-sheet-thickness detecting device that includes: a reference rollerprovided on a fixed rotation shaft and serving as a thickness referenceposition; a detection roller provided to face and come into contact withthe reference roller; a detection block in which the detection roller isprovided at one end of the detection block and the other end of theroller is rotatably fixed around a fulcrum shaft so that the detectionblock is rotated and displaced according to a thickness of a paper sheetpassing through between the reference roller and the detection roller; aholding block that holds at least the fulcrum shaft of the detectionblock; a first pressing member secured to the holding block to maintaincontact between the detection roller and the reference roller bypressing a part of the detection block, the first pressing member beingdisplaced according to rotation and displacement of the detection blockwhen the paper sheet passes through between the reference roller and thedetection roller; a displacement detector that detects a displacementamount of the first pressing member in a noncontact manner; and aplurality of detecting units each including the detection roller, thedetection block, the first pressing member, and the displacementdetector, the detecting units being arranged along the fulcrum shaft.

The object of the invention is effectively achieved by either comprisinga pitching suppressing unit that suppresses pitching of the detectionroller by applying a thrust pressure from both ends of the fulcrumshaft, or mounting the holding block in an upper baseplate via acompression spring and mounting the upper baseplate on a lower baseplateon which the rotation shaft of the reference roller is fixed.

The object of the invention is effectively achieved by either abutting,against the detection block, a thin-plate scraper that comes intocontact with the detection roller substantially vertically to remove aforeign substance adhered to the detection roller with rotation of thedetection roller, or mounting the scraper supported by a plate springintegrally formed in the lower baseplate, a resin scraper that comesinto contact with the reference roller with a predetermined pressure toremove a foreign substance adhered to the reference roller with rotationthereof, and providing an opening for discharging the removed foreignsubstance in the lower baseplate.

The object of the invention is effectively achieved by alternativelyarranging two types of detection blocks having a different distancebetween the rotation shaft of the detection roller and the fulcrum shaftthereof, so that the detection rollers are arranged in a staggeredmanner in a direction of the fulcrum shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram of a principle of thickness detectionby a paper-sheet-thickness detecting device according to the presentinvention.

FIG. 2 is a perspective view of a detection block in which a detectionroller is mounted.

FIG. 3 is a schematic diagram of a paper-sheet-thickness detectingdevice in which a plurality of detecting units are arranged along afulcrum shaft and a plurality of reference rollers are arranged along arotation shaft.

FIG. 4 depicts a state where a detection roller and a reference rollerare not contacted with each other.

FIG. 5 depicts output waveforms of a displacement detector (adisplacement sensor) for a comparison thereof.

FIG. 6 depicts a state where a plurality of detection blocks in whichdetection rollers are mounted are aligned along a fulcrum shaft, andthrust pressures are applied from both ends of the fulcrum shaft bycompression springs.

FIG. 7 depicts a paper-sheet-thickness detecting device in which twotypes of detection blocks having different distances between a fulcrumshaft of the detection block and rotation shafts of detection rollersare alternatively arranged so that detection rollers are arranged in astaggered manner.

FIG. 8 depicts the mechanism of FIG. 7 as viewed from a shaft direction.

FIG. 9 depicts scrapers for removing a foreign substance, the scrapersabutting against a reference roller.

FIG. 10 is an enlarged view of the scrapers shown in FIG. 9.

FIG. 11 is an example of a conventional paper-sheet-thickness detectingdevice.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

A paper-sheet-thickness detecting device according to the presentinvention will be explained below in detail with reference to theaccompanying drawings.

FIG. 1 is an explanatory diagram of a principle of thickness detectionby the paper-sheet-thickness detecting device according to the presentinvention. The thickness detecting device includes a reference roller 1with a rotation shaft being fixed, which serves as a reference positionof thickness, a detection roller 2 provided to come into contact withthe reference roller 1, a detection block 3 in which the detectionroller 2 is provided at one end and the other end thereof is rotatablyfixed around a fulcrum shaft 4 so that the detection block 3 is rotatedand displaced in a direction of the arrow according to a thickness ofthe paper sheet P passing through between the reference roller 1 and thedetection roller 2, a holding block 5 that holds at least the fulcrumshaft 4 of the detection block 3, a plate spring 6 made of metal andfixed to the holding block 5 to maintain contact between the detectionroller 2 and the reference roller 1 by pressing a part of the detectionblock 3, which is pushed upward and displaced according to rotation anddisplacement of the detection block 3 when the paper sheet P passesthrough between the reference roller 1 and the detection roller 2, adisplacement detector (a metal-plated displacement sensor) 7 thatdetects a displacement amount of the plate spring 6 in a noncontactmanner, and a signal processor (a sensor board) 8 that detects thethickness of the paper sheet P based on an output signal of thedisplacement sensor 7.

The principle of thickness detection is simply explained. When the papersheet P is transported and enters in between the reference roller 1 andthe detection roller 2, because the rotation shaft of the referenceroller 1 is secured, the detection roller is pushed upward by thethickness of the paper sheet P. Because the detection block 3 in whichthe detection roller 2 is mounted is rotatably supported about thefulcrum shaft 4, when the detection roller 2 moves upward, the detectionblock 3 also rotates upward. The plate spring 6 that contacts with thedetection block 3 at all times to push the detection block 3 downwardwith an elastic force is displaced upward corresponding to adisplacement of the detection block 3. The displacement sensor 7 outputsan electric signal as a change of distance (d) between the plate spring6 and the displacement sensor 7, and the signal processor 8 detects itas the thickness of the paper sheet P. As the metal-plated displacementsensor, a micro displacement sensor (product name: DS2001), manufacturedby Japan Systems Development Co., Ltd., can be used. A case that theplate spring 6 is made of metal is explained as an example, however, theplate spring 6 is not limited to be made of metal, and it may be made ofresin. In the case of resin, a distance sensor using laser or the likecan be used as the displacement sensor.

On the other hand, when the paper sheet P has passed through between thereference roller 1 and the detection roller 2, the detection block 3 ispushed downward by the elastic force of the plate spring 6, so that thereference roller 1 and the detection roller 2 comes into contact witheach other again.

FIG. 2 is a perspective view of an example of the detection block 3 inwhich the detection roller 2 is mounted. FIG. 2 depicts a state that alaminar scraper 9 for removing a foreign substance (a substance in whichdust or the like adhered to the paper sheet is transferred to theroller) adhered to the detection roller 2 with rotation of the detectionroller 2 is screwed to the detection block 3. Because the scraper 9abuts against the detection roller 2 substantially vertically, thescraper 9 can remove the foreign substance regardless of a rotationdirection of the detection roller 2.

FIG. 3 is a schematic diagram of an overall configuration of thepaper-sheet-thickness detecting device in which a plurality of detectingunits including the detection roller 2, the detection block 3, the platespring 6, and the displacement detector 7 are arranged along the fulcrumshaft 4 and a plurality of reference rollers 1 are arranged along therotation shaft. In the present embodiment, 12 of the detecting units arearranged in the direction of the fulcrum shaft, and correspondingreference rollers are arranged opposite thereto. The reference rollersdo not need to be arranged in a divided manner, and can be arranged asone long roller.

The rotation shaft of the reference roller is secured to a lowerbaseplate, and the holding block 5 fixed with the fulcrum shaft 4 of thedetection block 3 is mounted in an upper baseplate via a compressionspring.

The reason why the holding block is mounted in the upper baseplate viathe compression spring is to maintain the detection roller and thereference roller at an accurate position by pressing a pressing portionon the holding block side against a holding bearing by the compressionspring to thereby prevent a situation such that the thickness detectioncannot be performed when the detection roller 2 and the reference roller1 are away from each other to form a gap therebetween due to warpage ofthe base plate or the like, as shown in FIG. 4.

FIG. 5 depicts the output signal waveforms of the displacement sensor.The detection block 3 is pressed toward the reference roller in theopposite side thereof by the plate spring 6. However, the detectionroller trembles due to rough surfaces of the paper sheet while the papersheet passes through between the reference roller and the detectionroller, thereby causing pitching in the output signal waveform of thedisplacement sensor (FIG. 5(A)). It can be considered to increase thepressing force of the plate spring for reducing pitching; however, it isnot preferable because a reaction force against the holding blockincreases as a whole when the number of detecting units becomes larger.Therefore, it can be considered to dampen the movement of the respectivedetection blocks. Specifically, as shown in FIG. 6, a thrust pressure isapplied from both ends of the fulcrum shaft 4 of the detection block byusing the compression spring. Accordingly, the movement of therespective detection blocks is suppressed because the higher the degreeof adhesion between adjacent detection blocks, the higher the frictionalforce. As a result, pitching can be reduced to a small waveform as shownin FIG. 5(B).

FIG. 7(A) depicts a case that 12 detection blocks having the samedistance between the rotation shaft of the detection roller 2 and thefulcrum shaft 4 of the detection block 3 are arranged. When the papersheet enters in between the reference roller and the detection roller,the paper sheet bumps against 24 (12×2) detection rollers at a time.Therefore, the detection blocks fluctuate abruptly due to the shockthereof, thereby causing a kick in the output waveform of thedisplacement sensor (see FIG. 5). To reduce the kick, a method ofincreasing the pressing force by the plate spring 6 or increasing thethrust pressure with respect to the fulcrum shaft can be considered.However, if the pressing force of the plate spring is increased, a forceof 12 times the pressing force is applied to the holding block as anentire device, thereby causing problems of strength and paper jam.Further, if the thrust pressure is increased too much, the detectionblocks hardly move, thereby deteriorating detection sensitivity.

Therefore, as shown in FIG. 7(B), two types of detection blocks having adifferent distance between the rotation shaft of the detection roller 2and the fulcrum shaft 4 of the detection block 3 are used, these arealternatively arranged in a staggered manner (in a zig-zag manner), sothat the number of detection blocks against which the paper sheet bumpsat a time is decreased to reduce the shock, thereby alleviating the kickin the waveform. That is, in FIG. 7(B), when the paper sheet enters froman arrow direction, the paper sheet bumps against detection rollers indetection blocks of odd number from the left along the arrow direction,and thereafter, bumps against the detection rollers in the detectionblocks of even number. Therefore, the shock at the time of entrance ofthe paper sheet can be halved. The rotation shaft of the detectionroller in the odd detection blocks and the rotation shaft of thedetection roller in the even detection blocks can be arranged to beshifted by about 1 to several millimeters, respectively, before andafter the rotation shaft of the reference roller.

If the two types of detection blocks are alternatively arranged in thestaggered manner, as described above, a resistance force is appliedevenly to the front end of the paper sheet at the time of entrancethereof, thereby enabling to prevent a skew. Further, even if the twotype detection blocks are arranged in any combination in the same numberas a result, there is an effect of halving the shock at the time ofentrance of the paper sheet.

Further, if three or four types of detection blocks having a differentdistance between the rotation shaft of the detection roller 2 and thefulcrum shaft 4 of the detection block 3 are provided, the shock at thetime of entrance of the paper sheet can be alleviated to one third orone fourth, respectively.

FIG. 8 depicts the configuration of FIG. 7 as viewed from a shaftdirection.

FIG. 9 depicts a state where a scraper made of resin comes into contactwith the reference roller for removing a foreign substance adhered tothe reference roller (dust or the like adhered to the paper sheet istransferred to the roller) with rotation of the reference roller.Because the scraper comes into contact with the reference roller withthe entire surface, the foreign substance can be removed even when thereference roller rotates in any direction.

FIG. 10 is an enlarged view of the scraper, in which a portion thatcomes into contact with the reference roller has a round shape, and anopening for cleaning off dirt is provided in a plate spring portionintegrally formed with the scraper. Accordingly, the removed foreignsubstance is discharged to the outside of the thickness detectingdevice.

One end of the scraper is fixed to the lower baseplate via the platespring. Further, because the scraper is fixed via the plate spring, evenif the scraper is worn out, the scraper is not separated from thesurface of the reference roller, and thus a foreign-substance removingfunction is not deteriorated.

Due to the scraper shown in FIG. 2 and the scraper shown in FIG. 9,foreign substance can be removed from the reference roller and thedetection roller, thereby enabling accurate thickness detection.

1. A paper-sheet-thickness detecting device, comprising: a referenceroller provided on a fixed rotation shaft and serving as a thicknessreference position; a plurality of detection units each including adetection roller, a detection block, a first pressing member, and adisplacement detector, the detection units being arranged along afulcrum shaft of the detection block; and a holding block holds at leastthe fulcrum shaft, wherein the detection roller is provided to face andcome into contact with the reference roller; the detection block has afirst end at which the detection roller is provided and a second endwhich is rotatably fixed around the fulcrum shaft so that the detectionblock is rotated and displaced according to a thickness of a paper sheetpassing through between the reference roller and the detection roller;the first pressing member is fixed to the holding block to maintaincontact between the detection roller and the reference roller bypressing a part of the detection block, the first pressing member beingdisplaced according to turning and displacement of the detection blockwhen the paper sheet passes through between the reference roller and thedetection roller; and the displacement detector detects a displacementamount of the first pressing member in a noncontact manner.
 2. Thepaper-sheet-thickness detecting device of according to claim 1, furthercomprising a pitching suppressing unit that suppresses pitching of thedetection roller by applying a thrust pressure from both ends of thefulcrum shaft.
 3. The paper-sheet-thickness detecting device accordingto claim 1, wherein the holding block is mounted in an upper baseplatevia a compression spring, and the upper baseplate is mounted on a lowerbaseplate to which the rotation shaft of the reference roller issecured.
 4. The paper-sheet-thickness detecting device according toclaim 1, further comprising a thin-plate scraper fixed to the detectionblock, the thin-plate scraper coming into contact with the detectionroller substantially vertically to remove a foreign substance adhered tothe detection roller with rotation of the detection roller.
 5. Thepaper-sheet-thickness detecting device according to claim 3, wherein,further comprising: a resin scraper fixed to the lower baseplate via aplate spring integrally formed with the resin scraper, the resin scrapercoming into contact with the reference roller with a predeterminedpressure to remove a foreign substance adhered to the reference rollerwith rotation of the reference roller; and an opening for dischargingthe removed foreign substance, provided in the lower baseplate.
 6. Thepaper-sheet-thickness detecting device according to claim 5, wherein thescraper has a round-shaped end portion.
 7. The paper-sheet-thicknessdetecting device according to claim 1, wherein detection units includestwo type of detection units each having a different distance between therotation shaft of the detection roller and the fulcrum shaft of thedetection block, the two type of detection units being alternativelyarranged along the fulcrum shaft, so that the detection rollers arearranged in a staggered manner in a direction of an axis of the fulcrumshaft.
 8. The paper-sheet-thickness detecting device according to claim4, further comprising: a resin scraper fixed to the lower baseplate viaa plate spring integrally formed with the resin scraper, the resinscraper coming into contact with the reference roller with apredetermined pressure to remove a foreign substance adhered to thereference roller with rotation of the reference roller, and an openingfor discharging the removed foreign substance, provided in the lowerbaseplate.
 9. The paper-sheet-thickness detecting device according toclaim 8, wherein the scraper has a round-shaped end portion.